The following description relates to an adjustable steering column, and in particular, a release mechanism in an adjustable steering column.
A steering column may be adjustable in rake and telescope directions. In normal operation, the adjustable steering column is mounted in the vehicle and is selectively adjustable based on a locking condition. In a locked condition, the steering column must sufficiently resist movement or adjustment from a selected position and behave as a stiff extension of an interior vehicle structure. In an unlocked condition, the steering column may be freely adjusted by an operator in the rake and telescope directions.
In high-impact or crash scenarios, it is beneficial for the steering column to collapse, partially or fully, from its mounting position in an axial direction to absorb energy. A release mechanism may be provided to transition the steering column from a mounted, adjustable condition during normal operation to an energy absorbing condition during a high-impact or crash scenario.
To secure a steering column against adjustment by an operator, an upper jacket of the steering column is ultimately locked relative to the vehicle structure in a desired position. The upper jacket may be directly locked relative to the vehicle structure, or locked to a lower jacket section for added stiffness. The upper jacket is typically locked into place by a clamping force applied across the steering column. However, in such a configuration, a crash resistance force is coupled with the clamping force between the upper and lower jackets. Thus, the crash resistance force may be difficult to control.
Accordingly, it is desirable to decouple the crash resistance force mechanism from the clamp force mechanism to obtain better tuning of energy absorbing characteristics.